<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<input type="button" value="点我" id="btn1">
<script>
    var btn1 = document.getElementById('btn1');
//    btn1.onclick = function(e){
//        console.log("aa");
//    }
//    btn1.onclick = function(e){
//        console.log("bb");
//    }

    //type,listener,useCapture
    //事件类型
    //监听的函数
    //捕获事件的方式
    btn1.addEventListener('click',function(){
        console.log("aa")
    })
    btn1.addEventListener('click',function(){
        console.log("bb")
    })
    btn1.addEventListener('click',function(){
        console.log("cc")
    })
</script>
</body>
</html>